Wireless communication apparatus and method

ABSTRACT

A wireless communication apparatus includes an oscillator circuit configured to generate an oscillation signal corresponding to an oscillation frequency determined by an antenna, and a bias generator circuit configured to reconfigure an operation region mode of a transistor included in the oscillator circuit by adjusting a bias signal in response to an enable signal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 USC § 119(a) of KoreanPatent Application No. 10-2017-0050827 filed on Apr. 20, 2017, in theKorean Intellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND 1. Field

The following description relates to wireless communication technology.

2. Description of Related Art

A wireless transceiver operates using an oscillator configured to changean oscillation frequency in a desired range. The oscillator may includea combination of a capacitor and an inductor. For example, an analog LCvoltage control oscillator in which an oscillation frequency is changedin response to a change in capacitance of a capacitor of an oscillationcircuit varying based on a control voltage may be used.

In recent years, miniaturization of a transceiver has been required in,for example, a medical field. To this end, miniaturization of anexternal element related to radio frequency (RF) matching is required.Also, in an RC chip, a number of RF blocks and an area for each of theRF blocks may beneficially be minimized.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, a wireless communication apparatus includes anoscillator circuit configured to generate an oscillation signalcorresponding to an oscillation frequency determined by an antenna; anda bias generator circuit configured to reconfigure an operation regionmode of a transistor included in the oscillator circuit by adjusting abias signal in response to an enable signal.

The bias generator circuit may be configured to apply a first biasvoltage to the transistor in a reception mode and apply a second biasvoltage differing from the first bias voltage to the transistor in atransmission mode.

The bias generator circuit may be configured to apply the first biasvoltage to the transistor in a transient state interval of thetransmission mode and apply the second bias voltage to the transistor ina steady state interval after the transient state interval.

The bias generator circuit may be configured to apply the second biasvoltage to a gate node of the transistor included in the oscillatorcircuit in response to a delayed transmission target signal.

The bias generator circuit may be configured to determine a magnitude ofthe second bias voltage based on a common mode voltage of an outputsignal, a differential voltage of the output signal, and a threshold ofthe transistor.

The bias generator circuit may be configured to determine a magnitude ofthe first bias voltage based on a common mode voltage of an outputsignal.

The bias generator circuit may be configured to configure the transistorincluded in the oscillator circuit to operate in a saturation regionsuch that a current flowing through the antenna has a fundamentalfrequency in a transmission mode.

The bias generator circuit may be configured to prevent the transistorincluded in the oscillator circuit from operating in a deep trioderegion.

The bias generator circuit may be configured to supply the bias signalto the oscillator circuit by determining the bias signal such that anaverage value of the second bias voltage is greater than an averagevalue of a drain voltage of the transistor.

The bias generator circuit may be configured to apply the bias signal toa gate node of the transistor included in the oscillator circuit.

The antenna may include a capacitor and an inductor.

The capacitor may include a capacitor bank having a variable capacitancevalue.

In a process of transmitting a transmission target signal, theoscillator circuit may be configured to operate based on a first biasvoltage in a transient state interval and operate based on a second biasvoltage in a steady state interval, wherein the first bias voltage maybe different than the second bias voltage.

The wireless communication apparatus may further include a transmissionswitch configured to connect a capacitor to a source node of thetransistor included in the oscillator circuit in response to thewireless communication apparatus entering a transmission mode.

The oscillator circuit may include a transistor pair including twotransistors connected to each other, a capacitor connecting a gate nodeof a transistor of the two transistors and a drain node of the othertransistor of the two transistors, and a resistor connecting a gate nodeof a transistor of the two transistors and a gate node of the othertransistor of the two transistors.

The oscillator circuit may include a first transistor pair including twoN-type metal-oxide-semiconductor (NMOS) transistors mutually connectedto be oscillated using a resistor and a capacitor; and a secondtransistor pair including two P-type metal-oxide-semiconductor (PMOS)transistors mutually connected to be oscillated using a resistor and acapacitor.

The wireless communication apparatus may further include a delay circuitconfigured to provide, to the bias generator circuit, a delayedtransmission target signal generated by delaying a transmission targetsignal in response to the wireless communication apparatus entering atransmission mode.

The wireless communication apparatus may further include a resonanceswitch configured to switch on or off a connection between both ends ofthe antenna in response to a transmission target signal; and a currentsource switch configured to change a current flowing to the oscillatorcircuit in response to the transmission target signal.

The wireless communication apparatus may be configured to: control theresonance switch and the current source switch based on the transmissiontarget signal in a transmission mode; and control the resonance switchand the current source switch based on a quenching clock signal in areception mode.

The wireless communications apparatus may further include an antennacoupled to the oscillator circuit.

According to another general aspect, a wireless communication methodincludes determining an operation region of a transistor included in anoscillator circuit by adjusting a bias signal in response to an appliedsignal; and generating, by the oscillator circuit including thetransistor operating in the determined operation region, an oscillationsignal corresponding to an oscillation frequency determined by anantenna.

The generating, by the oscillator circuit including the transistoroperating in the determined operation region, the oscillation signalcorresponding to the oscillation frequency determined by the antenna,uses the antenna.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a wirelesscommunication apparatus.

FIG. 2 is a diagram illustrating an example of a wireless communication.

FIG. 3 is a diagram illustrating an example of an operation of awireless communication apparatus.

FIG. 4 is a diagram illustrating an example of a wireless communicationapparatus.

FIG. 5 is a diagram illustrating an example of an operation of awireless communication apparatus.

FIG. 6 is a diagram illustrating an example of an operation of anoscillator circuit included in a wireless communication apparatus.

FIG. 7 is a diagram illustrating an example of a wireless communicationapparatus.

FIG. 8 is a diagram illustrating an example of an operation of thewireless communication apparatus, such as the one of FIG. 7.

FIG. 9 is a diagram illustrating an example of a wireless communicationapparatus.

FIGS. 10 and 11 illustrate examples of a wireless communication method.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same or like elements. The drawings may not be toscale, and the relative size, proportions, and depiction of elements inthe drawings may be exaggerated for clarity, illustration, andconvenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings. Like numbers refer to like elementsthroughout the description of the figures.

It should be understood, however, that there is no intent to limit thisdisclosure to the particular embodiments disclosed. On the contrary,example embodiments are to cover all modifications, equivalents, andalternatives falling within the scope of the embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the,” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises,” “comprising,”“includes,” and/or “including,” when used herein, specify the presenceof stated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Unless otherwise defined, all terms, including technical and scientificterms, used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure pertains. Terms,such as those defined in commonly used dictionaries, are to beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art, and are not to be interpreted in anidealized or overly formal sense unless expressly so defined herein.

Regarding the reference numerals assigned to the elements in thedrawings, it should be noted that the same elements will be designatedby the same reference numerals, wherever possible, even though they areshown in different drawings. Also, in the description of embodiments,detailed description of well-known related structures or functions willbe omitted when it is deemed that such description will cause ambiguousinterpretation of the present disclosure.

FIG. 1 is a block diagram illustrating an example of a wirelesscommunication apparatus in accordance with an embodiment.

A wireless communication apparatus 100 includes an antenna 110, anoscillator circuit 120, and a bias generator circuit 130.

The antenna 110 is an element or a circuit configured to transmit asignal to an external area or receive a signal from an external source.The antenna 110 includes at least one capacitor and at least oneinductor. The capacitor includes a capacitor bank having a variablecapacitance. The antenna 110 is, for example, a circuit configured totransmit or receive a signal having a frequency similar to a resonancefrequency determined by either one or both of the capacitor and theinductor. The resonance frequency corresponds to an oscillationfrequency of the oscillator circuit 120.

The oscillator circuit 120 is a circuit configured to generated anoscillation signal. For example, the oscillator circuit 120 generates anoscillation signal having an oscillation frequency determined by theantenna 110 using the antenna 110. The wireless communication apparatus100 generates a data signal to be transmitted to an external area basedon the oscillation signal generated by an oscillator or receives a datasignal from an external source. In this disclosure, an oscillatorcircuit is also referred to as an oscillator for ease of description.

The oscillator circuit 120 uses the antenna 110 as a resonance inductorof the oscillator circuit 120. A single oscillator circuit may operateas a power oscillator in a process of transmission and is reconfiguredto operate as a super regenerative oscillator (SRO) in a process ofreception. Thus, the oscillator circuit 120 is reconfigurable so that itmay perform both an operation of an output end associated with arelatively large amount of power and an operation of a receiving endassociated with a relatively small amount of input power in a minimizedform factor.

A bias generator circuit 130 is a circuit configured to generate a biassignal and apply the generated bias signal. The bias generator circuit130 changes a region in which an amplifier or a transistor included inthe oscillator circuit 120 operates by adjusting the bias signal inresponse to an enable signal 131. Hereinafter, descriptions will beprovided based on an example in which an operation region of atransistor is changed based on a supplied bias signal and embodimentsare not limited thereto. The description is also applicable to anexample in which an entire amplifier circuit implemented as a transistoror an electronic device changes an operation region. In this disclosure,a bias generator circuit is also referred to as a bias generator forease of description.

The enable signal 131 is a signal determined based on at least one of anoperation mode and an operation speed of the wireless communicationapparatus 100. The enable signal 131 includes, for example, a signalused for indicating a transmission mode and a signal used for indicatinga reception mode. A process of determining the enable signal 131 will bedescribed in detail later.

A bias signal is a signal applied to the transistor included in theoscillator circuit 120. The bias signal includes, for example, a biasvoltage and a bias current. The bias signal may vary based on a class inwhich the transistor operates.

The operation region of the transistor is classified based on a positionof an operating point of a quiescent state in which a signal has notbeen applied. The operation region of the transistor is determined basedon at least one of the bias voltage and the bias current applied to thetransistor. The operation region of the transistor is classified into aclass A, a class AB, a class B, and a class C based on an amplifiablephase portion of the entire phase, for example, 360 degrees (°) of asignal input to the transistor.

When the transistor operates in the class A mode, the transistoramplifies a signal corresponding to the entire phase of 0° through 360°.For example, the transistor operating in the class A mode operated as alinear amplifier circuit of which an amplification rate is constantirrespective of an intensity of an input signal.

When the transistor operates in the class AB mode, the amplifiable phaseof the transistor is greater in a range between 0° and 180°, forexample, the class B and less than a range between 0° and 360°, forexample, the class A. For example, the transistor operating in the classAB is a transistor operating at an operating point between the class Aand the class B.

When the transistor operates in the class B mode, the transistoramplifies a signal corresponding to the entire phase of 0° through 180°.For example, the transistor operating in the class B mode is atransistor of which an operating point is located adjacent to athreshold voltage V_(th) of a characteristic of amplification. Thetransistor of the class B prevents a current from flowing at anoperating point, for example, a quiescent state, at which an alternatecurrent signal is 0. Through this, a power efficiency of the transistorcorresponding to the class B is maximized.

When the transistor operates in a class C mode, the transistor amplifiesa signal corresponding to a phase less than a phase between 0° and 180°.For example, the transistor operating in the class C is a transistor ofwhich an operating point is a voltage less than the threshold voltageV_(th) of a characteristic of amplification. The transistor operating inthe class C amplifies only a portion of waveform of an input signalinstead of the entire waveform of the input signal. The transistoroperating in the class C mode has a high amplification efficiency eventhough a waveform distortion may occur therein. When the oscillatorcircuit 120 operates in the class C mode, power consumption versusoutput of the oscillator circuit 120 may be improved and phase noise mayalso be alleviated.

The oscillator circuit 120 of the wireless communication apparatus 100secures a radio frequency (RF) gain by operating based on at least oneof the class A, the class B, and the class AB in the reception mode.Also, the wireless communication apparatus 100 operates in the class Cin the transmission mode, thereby achieving a high power efficiency inthe transmission mode. For example, when the wireless communicationapparatus 100 is in the reception mode, the oscillator circuit 120responds to an external signal input through the antenna 110 at a lowintensity. When the wireless communication apparatus 100 is in thetransmission mode, the oscillator circuit 120 transmits a signal to anexternal area at a low power and a high efficiency and the wirelesscommunication apparatus 100 is minimized. As such, the wirelesscommunication apparatus 100 changes an operation region of thetransistor included in the oscillator circuit 120 and a configuration ofthe oscillator circuit 120, thereby minimizing an amount of power usedfor transmitting and receiving a signal.

The wireless communication apparatus 100 is applicable to, for example,an RF integrated circuit (IC), a wireless transceiver having a smallform factor, a low power transmitter, the Internet of things (IoT) whereordinary, generally, non-computer related things, such as washers,refrigerators, and other devices are harnessed as additional nodes on acommunication network such as the internet, or intranets, and a medicalimplant communications system (MICS).

FIG. 2 is a diagram illustrating a wireless communication apparatus inaccordance with an embodiment.

A wireless communication apparatus 200 includes the antenna 110, theoscillator circuit 120, the bias generator circuit 130, a transmissionroute circuit 240, and a reception route circuit 250.

The antenna 110 includes a capacitor C_(RES) and an inductor L_(RES).The capacitor C_(RES) includes, for example, a capacitor bank having avariable capacitance value. An oscillation frequency of the oscillatorcircuit 120 is determined based on a capacitance value of the capacitorC_(RES) and an inductance value of the inductor L_(RES). The oscillationfrequency of the oscillator circuit 120 is, for example,f_(OSC)=1/(2π√{square root over (L_(RES)C_(RES)))}. Each frequencycorresponding to the oscillation frequency f_(osc) is, for example,w_(o).

The bias generator circuit 130 includes a bias voltage generator 231 anda bias current generator 232. Although FIG. 2 illustrates the biasvoltage generator 231 and the bias current generator 232 separate fromeach other, embodiments are not limited thereto. For example, a singlebias generator circuit generates a bias voltage V_(BIAS) and a biascurrent I_(BIAS) and provides the generated bias voltage V_(BIAS) andthe generated bias current I_(BIAS) to the oscillator circuit 120.

In an example of FIG. 2, the bias generator circuit 130 generates a biassignal based on a transmission applying signal TX_(EN). The biasgenerator circuit 130 supplies a first bias voltage V_(A) and areception bias current I_(RX) to the oscillator circuit 120 when thetransmission applying signal TX_(EN) is low, for example, 0. Also, thebias generator circuit 130 supplies a second bias voltage V_(C) and atransmission bias current I_(TX) to the oscillator circuit 120 when thetransmission applying signal TX_(EN) is high, for example, 1.

In this disclosure, a transmission applying signal TX_(EN) having avalue “high” indicates a transmission mode in which the wirelesscommunication apparatus 200 transmits a signal 209 to an external area.Also, a transmission applying signal TX_(EN) having a value “low”indicates a reception mode in which the wireless communication apparatus200 receives the signal 209 from an external source.

The first bias voltage V_(A) is, for example, a bias voltage thatconfigures a transistor of the oscillator circuit 120 to operate in aclass A. The second bias voltage V_(C) is, for example, a bias voltagethat reconfigures the transistor of the oscillator circuit 120 tooperate in a class C. The reception bias current I_(RX) indicates acurrent flowing from the oscillator circuit 120 to a ground during thereception mode. The transmission bias current I_(TX) indicates a currentflowing from the oscillator circuit 120 to the ground during thetransmission mode.

The transmission route circuit 240 is a circuit that is activated whilethe wireless communication apparatus 200 operates in the transmissionmode. For example, the transmission route circuit 240 is a circuit thatis activated by the wireless communication apparatus 200 to transmit thesignal 209 to an external area. In the transmission mode in which, forexample, the transmission applying signal TX_(EN) is high, thetransmission route circuit 240 controls a resonance switch 249 and acurrent source switch 248 based on a transmission target signal V_(DATA)241. In the reception mode, the transmission route circuit 240 controlsthe resonance switch 249 and the current source switch 248 based on aquenching clock signal QWG_(CLK) 242. Also, the oscillator circuit 120may perform a high-frequency conversion on the transmission targetsignal V_(DATA) 241 input through the transmission route circuit 240 tobe an oscillation frequency. As a size of a signal componentcorresponding to the oscillation frequency increases, an intensity of asignal to be transmitted to an external area is increased. Thus, theoscillator circuit 120 operates in the class C mode to amplify anoscillation frequency component, for example, a component correspondingto a fundamental frequency and improve a direct current (DC)-to-RF(DC-to-RF) power efficiency.

The transmission route circuit 240 opens the resonance switch 249 andcloses the current source switch 248 during an interval in which thetransmission target signal V_(DATA) 241 is valid, for example, aninterval in which data is present. Through this, the oscillator circuit120 oscillates using the antenna 110. Conversely, the transmission routecircuit 240 closes the resonance switch 249 and opens the current sourceswitch 248 during an interval in which the transmission target signalV_(DATA) 241 is invalid, for example, an interval in which the data isabsent. Through this, the oscillator circuit 120 intelligently preventsoscillation so as to prevent or significantly reduce power consumption.

While the wireless communication apparatus 200 operates in the receptionmode, the transmission route circuit 240 operates irrespective of thetransmission target signal V_(DATA) 241 and switches on or off theresonance switch 249 and the current source switch 248 based on thequenching clock signal QWG_(CLK) 242. The transmission route circuit 240opens the resonance switch 249 and closes the current source switch 248during an interval in which the quenching clock signal QWG_(CLK) 242 isvalid. Also, the transmission route circuit 240 closes the resonanceswitch 249 and opens the current source switch 248 during an interval inwhich the quenching clock signal QWG_(CLK) 242 is invalid.

The current source switch 248 changes a current of the oscillatorcircuit 120 based on a current control signal V_(IQWG). The currentsource switch 248 changes a current flowing to the oscillator circuit120 in response to the transmission target signal V_(DATA). Theresonance switch 249 switches an oscillation or a resonance of theoscillator circuit 120 and the antenna 110 based on a voltage controlsignal V_(VQWG). The resonance switch 249 switches on or off aconnection between both ends of the antenna 110 in response to thetransmission target signal V_(DATA). The voltage control signal V_(VQWG)is, for example, an inverse signal of the current control signalV_(IQWG). As illustrated in FIG. 2, the current control signal V_(IQWG)may be the transmission target signal V_(DATA) 241 in the transmissionmode and may be the quenching clock signal QWG_(CLK) 242 in thereception mode.

The reception route circuit 250 is a circuit that is activated while thewireless communication apparatus 200 operates in the reception mode.Also, the reception route circuit 250 is a circuit that is activated bythe wireless communication apparatus 200 to receive the signal 209 froman external source. When the reception route circuit 250 is activated,the oscillator circuit 120 operates in a class A mode to amplify an RFsignal of a relatively low intensity received from an external source.Also, in response to the oscillator circuit 120 operating based on thequenching clock signal QWG_(CLK) 242, the wireless communicationapparatus 200 quenches an RF-modulated signal received from the externalsource, thereby improving a receiving sensitivity and a response time.For example, the oscillator circuit 120 operating based on the quenchingclock signal QWG_(CLK) 242 starts oscillating in response to the signal209 having a frequency similar to an oscillation frequency beingreceived from the external source.

The reception route circuit 250 includes an envelope detector (ED)configured to detect an envelope of the signal 209 received from anexternal source and an analog-to-digital converter (ADC) configured toconvert the detected envelope into a digital signal. In the receptionmode, the wireless communication apparatus 200 receives the signal 209using the antenna 110, the oscillator circuit 120, and the receptionroute circuit 250, and is reconfigured to operate as asuper-regenerative receiver (SRR).

FIG. 3 is a diagram illustrating an example of an operation of awireless communication apparatus in accordance with an embodiment.

FIG. 3 illustrates an example of an operation of the wirelesscommunication apparatus, such as the one shown in FIG. 2 in a case inwhich the wireless communication apparatus enters a transmission mode.When the transmission applying signal TX_(EN) corresponding to a highstate is applied, the wireless communication apparatus generates thecurrent control signal V_(IQWG) and the voltage control signal V_(VQWG)based on the transmission target signal V_(DATA). As discussed above, anoscillation may be performed in an interval in which the transmissiontarget signal V_(DATA) is high, which may be represented as “OSC ON” inFIG. 3. Also, the oscillation may be suspended in an interval in whichthe transmission target signal V_(DATA) is low, which may be representedas “OSC OFF” in FIG. 3. The current control signal V_(IQWG) may beidentical to the transmission target signal V_(DATA). The voltagecontrol signal V_(VQWG) is, for example, an inverse signal of thetransmission target signal V_(DATA).

In a state in which the transmission applying signal TX_(EN) is low, forexample, in a reception mode, a bias generator circuit of the wirelesscommunication apparatus generates the first bias voltage V_(A). In astate in which the transmission applying signal TX_(EN) is high, forexample, in the transmission mode, the bias generator circuit of thewireless communication apparatus generates the second bias voltageV_(C). Thus, the wireless communication apparatus configures atransistor of an oscillator circuit to operate in a class A in thereception mode and adaptively reconfigures the transistor to operate ina class C in the transmission mode for selectively amplification andpower savings. An operation region of the transistor in reception modeis not limited to the foregoing example and thus, the wirelesscommunication apparatus operating in the reception mode also allows thetransistor of the oscillator circuit to operate in one of the class A, aclass B, and a class AB, according to one or more embodiments.

A transient state interval t₁ indicates a time used for a startup of theoscillator circuit. The startup may be a preparation operation for anoscillation of the oscillator circuit. The wireless communicationapparatus generates a signal to be transmitted to an external area at anormal intensity during a steady state interval t₂. A technique tominimize the transient state interval t₁ is beneficially employed in anenvironment in which a power efficiency and a high data transmissionrate are required.

FIG. 4 is a diagram illustrating a wireless communication apparatus inaccordance with an embodiment.

Referring to FIG. 4, a wireless communication apparatus 400 includes theantenna 110, the oscillator circuit 120, the bias generator circuit 130,and the reception route circuit 250, similarly to the wirelesscommunication apparatus 200 of FIG. 2.

Similarly to the example of FIG. 2, a transmission route circuit 440 ofthe wireless communication apparatus 400 uses a transmission targetsignal V_(DATA) 441 when the transmission applying signal TX_(EN) ishigh and uses a quenching clock signal QWG_(CLK) 442 when thetransmission applying signal TX_(EN) is low. The wireless communicationapparatus 400 controls a current source switch 448 and a resonanceswitch 449 based on the transmission target signal V_(DATA) 441 or thequenching clock signal QWG_(CLK) 442.

The transmission route circuit 440 further includes a delay circuit 443.The delay circuit 443 provides the transmission target signal V_(DATA_D)generated by delaying a transmission target signal V_(DATA) 441 to thebias generator circuit 130 in response to the wireless communicationapparatus 400 entering a transmission mode. In the transmission mode,the delay circuit 443 delays the transmission target signal V_(DATA) 441by a predetermined delay time Δt_(d) to generate the transmission targetsignal V_(DATA_D). The delay circuit may contain components known to oneof skill in the art after gaining a thorough understanding of thesubject disclosure. Such components may include capacitors, inductors,resistors, transistors, buffers, and the like.

In response to the delayed transmission target signal V_(DATA_D), thebias generator circuit 130 generates bias signals V_(BIAS) and I_(BIAS)and provides the bias signals V_(BIAS) and I_(BIAS) to the oscillatorcircuit. For example, the bias voltage generator 231 of the biasgenerator circuit 130 applies the second bias voltage V_(C) to a gatenode of a transistor included in the oscillator circuit in response tothe delayed transmission target signal V_(DATA_D). Thus, the biasvoltage generator 231 provides the first bias voltage V_(A) to theoscillator circuit 120 during the delay time Δt_(d) after thetransmission applying signal TX_(EN) is applied. Also, after the delaytime Δt_(d) elapses from a point in time at which the transmissionapplying signal TX_(EN) is applied, the bias voltage generator 231provides the second bias voltage V_(C) to the oscillator circuit 120.

FIG. 5 is a diagram illustrating an example of an operation of awireless communication apparatus in accordance with an embodiment.

FIG. 5 illustrates an example of controlling a bias voltage V_(BIAS) ofan oscillator circuit using a delayed transmission target signalV_(DATA_D) generated by delaying a transmission target signal for apredetermined delay time Δt_(d) in response to the wirelesscommunication apparatus of FIG. 4 entering a transmission mode.

The wireless communication apparatus generates the current controlsignal V_(IQWG) to correspond to substantially the same timing as thetransmission target signal V_(DATA), and generates the voltage controlsignal V_(VQWG) based on an inverse signal of the transmission targetsignal V_(DATA).

As illustrated in FIG. 5, the wireless communication apparatus generatesthe delayed transmission target signal V_(DATA_D) and generates the biasvoltage V_(BIAS) based on the delayed transmission target signalV_(DATA_D). For example, while the transmission target signal V_(DATA_D)is in a low state, the wireless communication apparatus applies thefirst bias voltage V_(A) to an oscillator circuit as the bias voltageV_(BIAS). When the delayed transmission target signal V_(DATA_D) entersa high state, the wireless communication apparatus applies the secondbias voltage V_(C) to the oscillator circuit as the bias voltageV_(BIAS). Since the delayed transmission target signal V_(DATA_D) is asignal delayed by the delay time Δt_(d), a transistor of the oscillatorcircuit operates, for example, in a class AB mode during the delay timeΔt_(d) after the wireless communication apparatus enters a transmissionmode. However, a type of class is not limited to the class AB and thus,the oscillator circuit may also operate in a class A or a class B. Afterthe delay time Δt_(d) elapses, the transistor of the oscillator operatesin a class C mode.

A bias generator circuit applies the first bias voltage V_(A) to thetransistor in a transient state interval t′₁ in the transmission mode.Also, the bias generator circuit applies the second bias voltage V_(C)to the transistor in a steady state interval t′₂ after the transientstate interval t′₁ elapses. Thus, the oscillator circuit operates in theclass AB mode based on the first bias voltage V_(A) in the transientstate interval t′₁ for each process of transmitting the transmissiontarget signal. Also, the oscillator circuit operates in the class C modebased on the second bias voltage V_(C) in the steady state interval t′₂.

The transistor of the oscillator circuit included in the wirelesscommunication apparatus is started up in the transient state intervalt′₁. The oscillator circuit operates to generate a signal to betransmitted to an external area at a normal amplitude in the steadystate interval t′₂. In an example of FIG. 5, the wireless communicationapparatus dynamically adjusts the bias voltage V_(BIAS) applied to thetransistor of the oscillator circuit through a delay circuit in thetransmission mode so as to reduce the transient state interval t′₁ incomparison to the transient state interval t₁ of FIG. 3. By reducing thetransient state interval the wireless communication apparatus realizes afast startup 510 and realizes a high efficiency of transmission power.

Also, the wireless communication apparatus stably terminates anoscillation of the signal transmitted to an external area at a point intime at which the transmission target signal V_(DATA) is to be low basedon the current control signal V_(IQWG) and the voltage control signalV_(VQWG) so as to remove a lagging residual inefficiency 520 of theoscillation.

FIG. 6 is a diagram illustrating an operation of an oscillator circuitincluded in a wireless communication apparatus in accordance with anembodiment.

FIG. 6 illustrates a half circuit of the oscillator circuit 120connected to the antenna 110 to perform an oscillation. The antenna 110includes an inductor L_(RES) and a capacitor C_(RES) connected inparallel.

The oscillator circuit 120 includes a transistor pair including twotransistors connected to each other. The transistor pair also includesthe capacitor C_(OSC) connecting a gate node of one transistor, forexample, M₂ of the two transistors and a drain node of the othertransistor, and a resistor R_(OSC) connecting the gate node of onetransistor, for example, M₂ of the two transistors and a gate node ofthe other transistor. When a transistor, for example, M₂ (as seen, forexample, in FIG. 7) included in the oscillator circuit 120 operates in adeep triode region, a resistor R_(ON) may be present as a resistorbetween a drain node and a source node in a region 121 between a drainand a source of a transistor.

FIG. 7 is a diagram illustrating a wireless communication apparatus inaccordance with an embodiment.

FIG. 7 illustrates a circuit of the wireless communication apparatus ofFIG. 4. The antenna 110 includes one or more inductors L_(RES) 711 andone or more capacitors 712. The capacitor 712, in this example, includesa capacitor bank. A capacitance value of the capacitor bank iscontrolled based on a control code.

An oscillator circuit includes, for example, two transistor pairs. In anexample of FIG. 7, the oscillator circuit includes a first transistorpair 721 and a second transistor pair 722.

A transistor pair included in the oscillator circuit operates as anegative resistance generator circuit and is implemented as, forexample, a cross-connected pair. In terms of an N-typemetal-oxide-semiconductor (NMOS) transistor, a voltage applied to a gatenode of a transistor in the transistor pair is set to be lower than acommon mode voltage of an output signal. In terms of a P-typemetal-oxide-semiconductor (PMOS) transistor, the voltage applied to thegate node of the transistor in the transistor pair is set to be higherthan the common mode voltage of the output signal.

The first transistor pair 721 includes two NMOS transistors M₂ and M₃connected to each other to oscillate using a resistor and a capacitor.When receiving the bias signal V_(BIASN), the first transistor pair 721operates in a region corresponding to a voltage of the bias signalV_(BIASN). The voltage of the bias signal V_(BIASN) is determined to bethe second bias voltage V_(C) in a transmission mode and determined tobe the first bias voltage V_(A) in a reception mode. As illustrated inthe bias generator circuit 130 of FIG. 7, the bias signal V_(BIASN) isan output signal, for example, V_(A) or V_(C) of a multiplexer (MUX)determined based on an operation mode and an operation speed of thewireless communication apparatus. The bias generator circuit 130 appliesthe first bias voltage V_(A) to the transistors M₂ and M₃ in thereception mode and applies the second bias voltage V_(C) that isdifferent from the first bias voltage V_(A) to the transistors M₂ and M₃in the transmission mode. For example, the second bias voltage V_(C)corresponding to the first transistor pair 721 is lower than the firstbias voltage V_(A).

The second transistor pair 722 includes, for example, two PMOStransistors M₄ and M₅ connected to each other to oscillate using aresistor and a capacitor. When receiving the bias signal V_(BIASP), thesecond transistor pair 722 operates in a region corresponding to avoltage of the bias signal V_(BIASP). The voltage of the bias signalV_(BIASP) is determined to be the second bias voltage V_(PC) in thetransmission mode and determined to be the first bias voltage V_(PA) inthe reception mode. As illustrated in the bias generator circuit 130 ofFIG. 7, the bias signal V_(BIASP) is an output signal, for example,V_(PA) or V_(PC) of an MUX determined based on an operation mode and anoperation speed of the wireless communication apparatus. Also, thewireless communication apparatus may supply a supply power V_(DD) to thesecond transistor pair 722. The bias generator circuit 130 applies thefirst bias voltage V_(PA) to the transistors M₄ and M₅ in the receptionmode and applies the second bias voltage V_(PC) that is different fromthe first bias voltage V_(PA) to the transistors M₄ and M₅ in thetransmission mode. For example, the second bias voltage V_(PC)corresponding to the second transistor pair 722 is higher than the firstbias voltage V_(PA).

In the reception mode, the bias generator circuit 130 determines amagnitude of a first bias voltage based on a common mode voltage of anoutput signal. For example, the bias generator circuit 130 determinesthe first bias voltage such that the first bias voltage is identical orsimilar in magnitude to the common mode voltage of the output signal.Through this, the oscillator circuit 120 receives the same voltage asthe common mode voltage. In the reception mode, the bias generatorcircuit 130 determines the first bias voltage V_(A) of the bias signalV_(BIASN) corresponding to the first transistor pair 721 to be, forexample, V_(BIASN)−V_(CM)≈0. Also, in the reception mode, the biasgenerator circuit 130 determines the first bias voltage V_(PA) of thebias signal V_(BIASP) corresponding to the second transistor pair 722 tobe, for example, V_(BIASP)−V_(CM)≈0.

In the transmission mode, the bias generator circuit 130 determines amagnitude of the second bias voltage V_(C) of the bias signal V_(BIASN)corresponding to the first transistor pair 721 based on a common modevoltage V_(CM) of an output signal, a differential voltage A_(T) of theoutput signal, and a threshold V_(THN) of a transistor. The biasgenerator circuit 130 determines the magnitude of the second biasvoltage V_(C) corresponding to the first transistor pair 721 to be, forexample, V_(BIASN)<V_(CM)−A_(T)+V_(THN). In this example, A_(T) denotesan output amplitude and is obtained using, for example,V_(outp)−V_(outn). The bias generator circuit 130 determines the secondbias voltage V_(C) corresponding to the first transistor pair 721 usingthe aforementioned equation so as to configure the NMOS transistor ofthe oscillator circuit 120 to operate in, for example, a saturationregion.

Also, the bias generator circuit 130 determines a magnitude of thesecond bias voltage V_(PC) of the bias signal V_(BIANSP) correspondingto the second transistor pair 722 based on the common mode voltageV_(CM) of the output signal, the differential voltage A_(T) of theoutput signal, and the threshold V_(THN) of the transistor. The biasgenerator circuit 130 determines the magnitude of the second biasvoltage V_(PC) corresponding to the second transistor pair 722 to be,for example, V_(BIASP)<V_(CM)−A_(T)+|V_(THP)|. The bias generatorcircuit 130 determines the second bias voltage V_(PC) corresponding tothe second transistor pair 722 using, for example, the aforementionedequation, according to embodiments, so as to allow the PMOS transistorof the oscillator circuit 120 to operate in the saturation region.

The transmission route circuit 440 includes a current power switch M₁448, a resonance switch M₆ 449, and the delay circuit 443. Since thedescription of FIG. 4 is applicable here, repeated description withrespect to operations of the current power switch M₁ 448, the resonanceswitch M₆ 449, and the delay circuit 443 will be omitted. Both ends ofthe resonance switch M₆ 449 correspond to a differential voltagecorresponding to a signal to be transmitted to an external area. Forexample, a voltage of one end of the resonance switch M₆ 449 is obtainedusing V_(outp)+V_(CM) and a voltage of the other end is obtained usingV_(outn)+V_(CM).

Also, in response to the wireless communication apparatus entering thetransmission mode, a transmission switch SW_(TX) connects a capacitor toa source node of the transistor included in the oscillator circuit. Inthis example, the source node of the transistor included in theoscillator circuit is connected to a ground via the capacitor.

FIG. 8 is a diagram illustrating an example of an operation of awireless communication apparatus, such as the one illustrated in FIG. 7.

FIG. 8 illustrates an example of controlling bias signals V_(BIASN) andV_(BIASP) of the oscillator circuit using a delayed transmission targetsignal V_(DATA_D) generated by delaying a transmission target signal fora delay time Δt_(d) in response to the wireless communication apparatusof FIG. 7 entering a transmission mode. In FIG. 8, the transmissiontarget signal V_(DATA), the current control signal V_(IQWG), the voltagecontrol signal V_(VQWG), and the delayed transmission target signalV_(DATA_D) may be the same, or similar to, those of FIG. 5.

The wireless communication apparatus generates a bias voltage of thebias signal V_(BIASN) supplied to a first transistor pair and a biasvoltage of the bias signal V_(BIASP) supplied to a second transistorpair based on the delayed transmission target signal V_(DATA_D).

Transistors, for example, M₂, M₃, M₄, and M₅ of the first transistorpair and the second transistor pair apply first bias voltages V_(A) andV_(PA) to the first transistor pair and the second transistor pair inthe transient state interval after entering a transmission mode. Afterthe transient state interval elapses, the transistors apply second biasvoltage V_(C) and V_(PC) to the first transistor pair and the secondtransistor pair in the steady state interval t′₂.

Through this, the first transistor pair and the second transistor pairof the oscillator circuit in the wireless communication apparatus arestarted up in the transient state interval t′₁ and operate to generate asignal V_(TX) to be transmitted to an external area at a normalamplitude in the steady state interval t′₂. In this example, the signalV_(TX) is obtained using V_(outp)−V_(outn). The wireless communicationapparatus allows the oscillator circuit to operate in one of a class A,a class B, and a class AB in an initial interval during which thetransmission target signal V_(DATA) is high.

An oscillation interval ratio T is represented as, for example,T=t′₂/(t′₁+t′₂). As the oscillation interval ratio increases, thetransient state interval t′₁ is minimized and thus, an output efficiencyis significantly improved. The wireless communication apparatusdynamically adjusts the oscillation interval ratio based on, forexample, a signal status.

FIG. 9 is a diagram illustrating an example of a wireless communicationapparatus in accordance with an embodiment.

FIG. 9 illustrates a circuit of a wireless communication apparatus, suchas the one of FIG. 2. The antenna 110 includes, for example, thecapacitor C_(RES), the inductor L_(RES), and a capacitor bank.

The oscillator circuit 120 includes a transistor pair including twotransistors M₂ and M₃.

The transmission route circuit 440 generates the voltage control signalV_(VQWG) and the current control signal V_(IQWG) based on either thetransmission target signal V_(DATA) or the quenching clock signalQWG_(CLK) in response to the transmission applying signal TX_(EN). Thetransmission route circuit 440 controls the resonance switch M₆ 449based on the voltage control signal V_(VQWG) and controls the currentsource switch M₁ 448 based on the current control signal V_(IQWG). Thetransmission route circuit 440 also includes the delay circuit 443configured to delay the transmission target signal V_(DATA).

A bias generator circuit 930 generates a bias signal V_(BIASN) as anoutput signal of a multiplexer selected based on an operation mode andan operation speed of the wireless communication apparatus. In responseto the wireless communication apparatus entering a transmission mode,the bias generator circuit 930 determines the bias signal V_(BIASN) tobe, for example, V_(BIASN)<V_(DD)−A_(T)+|V_(THN)|, where V_(DD) denotesa voltage of a supply power supplied to the wireless communicationapparatus, A_(T) denotes an amplitude of a signal to be transmitted toan external area, and V_(THN) denotes a threshold voltage of thetransistors M₂ and M₃ included in the oscillator circuit 120.

Since the descriptions of FIGS. 1 through 8 are also applicable here,repeated description of the FIGS. will be omitted for clarity andconciseness.

FIGS. 10 and 11 illustrate examples of a wireless communication method.

FIG. 10 is a flowchart illustrating an example of a wirelesscommunication method.

In operation 1010, a wireless communication apparatus determines anoperation region of a transistor included in the oscillator circuitconnected to an antenna by adjusting a bias signal in response to anenable signal.

In operation 1020, by using the antenna, the oscillator circuit of thewireless communication apparatus generates an oscillation signalcorresponding to an oscillation frequency determined by, for example,any one or any two or more of the geometry, the material, and theoperational characteristics of the antenna. In this example, theoscillator circuit includes the transistor that operates in thedetermined operation region.

FIG. 11 is a flowchart illustrating an example of a wirelesscommunication method.

In operation 1110, a wireless communication apparatus is in a standbystate. For example, the wireless communication apparatus is in standbyuntil an operational mode is determined.

In operation 1120, the wireless communication apparatus determineswhether the mode is a transmission mode or a reception mode. Thewireless communication apparatus determines the mode based on atransmission enable signal.

In operation 1130, the wireless communication apparatus applies a biassignal corresponding to a class C to an oscillator in response to thewireless communication apparatus entering the transmission mode.

In operation 1140, the wireless communication apparatus determineswhether a high-efficiency fast startup is set.

In operation 1150, when the fast startup is set, the wirelesscommunication apparatus dynamically supplies the bias signal. Thewireless communication apparatus applies the bias signal such that theoscillator operates in a class AB mode in operation 1151. In operation1152, the wireless communication apparatus delays a transmission targetsignal. Also, the wireless communication apparatus adjusts the biassignal such that the oscillator operates in a class C mode in operation1153.

In operation 1160, the wireless communication apparatus operates atransmission route circuit to transmit the transmission target signal toan external area such as, for example, a suitably configured receiverdevice or devices.

When entering the reception mode, the wireless communication apparatusapplies a bias signal corresponding to a class AB to the oscillator inoperation 1170. In operation 1180, the wireless communication apparatusoperates a reception route circuit to receive a signal from an externalsource such as, for example, an external transmitting device or devices.

Operations of the wireless communication apparatus are not limited tothe examples of FIGS. 10 and 11 and may be combined with the operationsdescribed with reference to FIGS. 1 through 9.

The wireless communication apparatus beneficially provides high powerand high power efficiency characteristics in the transmission mode and alow power and high signal gain characteristics in the reception mode.

The wireless communication apparatus and components thereof in FIGS.1-11 that perform the operations described in this application areimplemented by hardware components configured to perform the operationsdescribed in this application that are performed by the hardwarecomponents. Examples of hardware components that may be used to performthe operations described in this application where appropriate includecontrollers, sensors, generators, drivers, memories, comparators,arithmetic logic units, adders, subtractors, multipliers, dividers,integrators, oscillators, signal generators, inductors, capacitors,buffers, and any other electronic components configured to perform theoperations described in this application. In other examples, one or moreof the hardware components that perform the operations described in thisapplication are implemented by computing hardware, for example, by oneor more processors or computers. A processor or computer may beimplemented by one or more processing elements, such as an array oflogic gates, a controller and an arithmetic logic unit, a digital signalprocessor, a microcomputer, a programmable logic controller, afield-programmable gate array, a programmable logic array, amicroprocessor, or any other device or combination of devices that isconfigured to respond to and execute instructions in a defined manner toachieve a desired result. In one example, a processor or computerincludes, or is connected to, one or more memories storing instructionsor software that are executed by the processor or computer. Hardwarecomponents implemented by a processor or computer may executeinstructions or software, such as an operating system (OS) and one ormore software applications that run on the OS, to perform the operationsdescribed in this application. The hardware components may also access,manipulate, process, create, and store data in response to execution ofthe instructions or software. For simplicity, the singular term“processor” or “computer” may be used in the description of the examplesdescribed in this application, but in other examples multiple processorsor computers may be used, or a processor or computer may includemultiple processing elements, or multiple types of processing elements,or both. For example, a single hardware component or two or morehardware components may be implemented by a single processor, or two ormore processors, or a processor and a controller. One or more hardwarecomponents may be implemented by one or more processors, or a processorand a controller, and one or more other hardware components may beimplemented by one or more other processors, or another processor andanother controller. One or more processors, or a processor and acontroller, may implement a single hardware component, or two or morehardware components. A hardware component may have any one or more ofdifferent processing configurations, examples of which include a singleprocessor, independent processors, parallel processors,single-instruction single-data (SISD) multiprocessing,single-instruction multiple-data (SIMD) multiprocessing,multiple-instruction single-data (MISD) multiprocessing, andmultiple-instruction multiple-data (MIMD) multiprocessing.

The methods illustrated in FIGS. 1-11 that perform the operationsdescribed in this application are performed by either one or both ofanalog electrical components, mixed mode components, and computinghardware, for example, by one or more processors or computers,implemented as described above executing instructions or software toperform the operations described in this application that are performedby the methods. For example, a single operation or two or moreoperations may be performed by a single processor, or two or moreprocessors, or a processor and a controller. One or more operations maybe performed by one or more processors, or a processor and a controller,and one or more other operations may be performed by one or more otherprocessors, or another processor and another controller. One or moreprocessors, or a processor and a controller, may perform a singleoperation, or two or more operations.

Instructions or software to control computing hardware, for example, oneor more processors or computers, to implement the hardware componentsand perform the methods as described above may be written as computerprograms, code segments, instructions or any combination thereof, forindividually or collectively instructing or configuring the one or moreprocessors or computers to operate as a machine or special-purposecomputer to perform the operations that are performed by the hardwarecomponents and the methods as described above. In one example, theinstructions, firmware, design model, or software include machine codethat is directly executed by the one or more processors or computers,such as machine code produced by a compiler. In another example, theinstructions, firmware, analog logic, or software includes higher-levelcode that is executed by the one or more processors or computer using aninterpreter. The instructions or software may be written using anyprogramming language based on the block diagrams and the flow chartsillustrated in the drawings and the corresponding descriptions in thespecification, which disclose algorithms for performing the operationsthat are performed by the hardware components and the methods asdescribed above.

The instructions, firmware, or software to control computing hardware,for example, one or more processors or computers, to implement thehardware components and perform the methods as described above, and anyassociated data, data files, and data structures, may be recorded,stored, or fixed in or on one or more non-transitory computer-readablestorage media. Examples of a non-transitory computer-readable storagemedium include read-only memory (ROM), random-access memory (RAM), flashmemory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs,DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, magnetictapes, floppy disks, magneto-optical data storage devices, optical datastorage devices, hard disks, solid-state disks, and any other devicethat is configured to store the instructions or software and anyassociated data, data files, and data structures in a non-transitorymanner and provide the instructions or software and any associated data,data files, and data structures to one or more processors or computersso that the one or more processors or computers can execute theinstructions. In one example, the instructions or software and anyassociated data, data files, and data structures are distributed overnetwork-coupled computer systems so that the instructions and softwareand any associated data, data files, and data structures are stored,accessed, and executed in a distributed fashion by the one or moreprocessors or computers.

Although specific terminology has been used in this disclosure, it willbe apparent after an understanding of the disclosure of this applicationthat different terminology may be used to describe the same features,and such different terminology may appear in other applications.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. A wireless communication apparatus comprising: anoscillator circuit configured to generate an oscillation signalcorresponding to an oscillation frequency determined by an antenna; anda bias generator circuit configured to reconfigure an operation regionmode of a transistor included in the oscillator circuit by adjusting abias signal in response to an enable signal.
 2. The wirelesscommunication apparatus of claim 1, wherein the bias generator circuitis configured to apply a first bias voltage to the transistor in areception mode and apply a second bias voltage differing from the firstbias voltage to the transistor in a transmission mode.
 3. The wirelesscommunication apparatus of claim 2, wherein the bias generator circuitis configured to apply the first bias voltage to the transistor in atransient state interval of the transmission mode and apply the secondbias voltage to the transistor in a steady state interval after thetransient state interval.
 4. The wireless communication apparatus ofclaim 2, wherein the bias generator circuit is configured to apply thesecond bias voltage to a gate node of the transistor included in theoscillator circuit in response to a delayed transmission target signal.5. The wireless communication apparatus of claim 2, wherein the biasgenerator circuit is configured to determine a magnitude of the secondbias voltage based on a common mode voltage of an output signal, adifferential voltage of the output signal, and a threshold of thetransistor.
 6. The wireless communication apparatus of claim 2, whereinthe bias generator circuit is configured to determine a magnitude of thefirst bias voltage based on a common mode voltage of an output signal.7. The wireless communication apparatus of claim 1, wherein the biasgenerator circuit is configured to configure the transistor included inthe oscillator circuit to operate in a saturation region such that acurrent flowing through the antenna has a fundamental frequency in atransmission mode.
 8. The wireless communication apparatus of claim 1,wherein the bias generator circuit is configured to prevent thetransistor included in the oscillator circuit from operating in a deeptriode region.
 9. The wireless communication apparatus of claim 1,wherein the bias generator circuit is configured to supply the biassignal to the oscillator circuit by determining the bias signal suchthat an average value of the second bias voltage is greater than anaverage value of a drain voltage of the transistor.
 10. The wirelesscommunication apparatus of claim 1, wherein the bias generator circuitis configured to apply the bias signal to a gate node of the transistorincluded in the oscillator circuit.
 11. The wireless communicationapparatus of claim 1, wherein the antenna comprises a capacitor and aninductor.
 12. The wireless communication apparatus of claim 11, whereinthe capacitor comprises a capacitor bank having a variable capacitancevalue.
 13. The wireless communication apparatus of claim 1, wherein, ina process of transmitting a transmission target signal, the oscillatorcircuit is configured to operate based on a first bias voltage in atransient state interval and operate based on a second bias voltage in asteady state interval, wherein the first bias voltage is different thanthe second bias voltage.
 14. The wireless communication apparatus ofclaim 1, further comprising: a transmission switch configured to connecta capacitor to a source node of the transistor included in theoscillator circuit in response to the wireless communication apparatusentering a transmission mode.
 15. The wireless communication apparatusof claim 1, wherein the oscillator circuit comprises a transistor pairincluding two transistors connected to each other, a capacitorconnecting a gate node of a transistor of the two transistors and adrain node of the other transistor of the two transistors, and aresistor connecting a gate node of a transistor of the two transistorsand a gate node of the other transistor of the two transistors.
 16. Thewireless communication apparatus of claim 1, wherein the oscillatorcircuit comprises: a first transistor pair including two N-typemetal-oxide-semiconductor (NMOS) transistors mutually connected to beoscillated using a resistor and a capacitor; and a second transistorpair including two P-type metal-oxide-semiconductor (PMOS) transistorsmutually connected to be oscillated using a resistor and a capacitor.17. The wireless communication apparatus of claim 1, further comprising:a delay circuit configured to provide, to the bias generator circuit, adelayed transmission target signal generated by delaying a transmissiontarget signal in response to the wireless communication apparatusentering a transmission mode.
 18. The wireless communication apparatusof claim 1, further comprising: a resonance switch configured to switchon or off a connection between both ends of the antenna in response to atransmission target signal; and a current source switch configured tochange a current flowing to the oscillator circuit in response to thetransmission target signal.
 19. The wireless communication apparatus ofclaim 18, wherein the wireless communication apparatus is configured to:control the resonance switch and the current source switch based on thetransmission target signal in a transmission mode; and control theresonance switch and the current source switch based on a quenchingclock signal in a reception mode.
 20. The wireless communicationsapparatus of claim 1, further comprising an antenna coupled to theoscillator circuit.
 21. A wireless communication method comprising:determining an operation region of a transistor included in anoscillator circuit by adjusting a bias signal in response to an appliedsignal; and generating, by the oscillator circuit comprising thetransistor operating in the determined operation region, an oscillationsignal corresponding to an oscillation frequency determined by anantenna.
 22. The wireless communication method of claim 21, wherein thegenerating, by the oscillator comprising the transistor operating in thedetermined operation region, the oscillation signal corresponding to theoscillation frequency determined by the antenna, uses the antenna.